In the project navigator in Xcode, I am not sure what the ? is trying to tell me next to the file name.

I am sure it is not a coincidence that this is the same file that I dragged from my root directory for the project to the Classes folder (because the .mm file was there and I wanted them to be together). The project still compiles just fine, however my code sense broke recently and I am wondering whether this may be part of the issue.

Thanks. In case someone else reads this, just right click on the file and goto Source Control->Add. This will turn ? to A. So, basically: ? means not part of source control. A means added to source control, but not modified. M means it is added to source control and is modified.
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Farhan HafeezFeb 13 '13 at 6:44

Also, if you see the question mark against a file that you know is tracked, and the Source Control->Refresh Status menu option doesn't change anything, try just quitting and restarting Xcode. Sigh.
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Matt GibsonJan 14 at 20:30